The present invention relates to a sheet finisher which center folds and binds sheets that have been outputted from an image forming apparatus such as a copier, printer, or the like.
A sheet finisher makes a sheet bundle by using a stacking means to stack sheets on which images have been formed by an image forming apparatus, and binds the sheet bundle, thereby creating a book or a document. It is commonly used as a peripheral equipment connected to an image forming apparatus.
There are commonly used means for binding a sheet bundle, one is a means that uses an apparatus, called stapler, which uses staples to bind one edge of the sheet bundle, and another is a means that uses binding tape with hot-melt glue applied thereon and aligns and binds a prescribed side edge of the sheet bundle while heating the tape (for example, see patent document 1).
It is preferable that sheet bundles to be bound as stated above be the same size in terms of convenience of processing, and, for example, when A3-size sheets are to be bound, the sheets are first Z-folded and then the resulting A4-size sheets are bundled and bound (for example, see patent document 2).
However, in case of binding by using the above-mentioned binding tape, when a sheet bundle having Z-folded sheets only or a sheet bundle including Z-folded sheets is bound, binding is not ensured and sheets may fall out occasionally.
Furthermore, in order to make binding more secure, in some cases, a sheet bundle which has been bounded by staples, is further bound by binding tape.
In order to conduct such procedures, a sheet finisher is required to have a folding means for Z-folding or center-folding sheets, and a binding means for binding a sheet bundle by using staples or binding tape, so that users can properly select those means and conduct prescribed procedures. Accordingly, the apparatus is usually of considerable size or is connected to two or more pieces of other apparatus which includes the above-mentioned means.
Patent document 1 represents Published Unexamined Japanese Patent Application No. Tokkaihei 7-89259 (pages 1 and 2), and Patent document represents Published Unexamined Japanese Patent Application No. Tokkaihei 10-194586 (page 1).